Specimens from human ocular tissues with various diseases, such as uveitis, conjunctival and corneal diseases, metabolic genetic diseases, and tumors were studied using immunoperoxidase technique as well as light and electron microscopic evaluation. In uveitis, immunocompetent cells and lymphokines are critical in the reflection of clinical diagnosis, disease course, and prognosis. In non-uveitis conditions, alteration of cellular membrane surface markers and intracytoskeleton on the ocular resident cells may imply damage and abnormalities in these diseases. Elucidating the role of the relationships between infiltrating inflammatory cells and other cells in the clinical behavior of various diseases will increase our understanding of human ocular disorders.